CVE-2026-64679: Atlantis: Path Traversal in Atlantis Workspace Handling Allows Out-of-Bounds Directory Deletion/Creation
Summary Atlantis versions >= 0.19.8 and < 0.45.0 did not consistently validate user-controlled workspace values before using them to construct local workspace paths.
A crafted workspace value containing path traversal segments could cause Atlantis to resolve workspace paths outside the intended per-pull workspace directory. In vulnerable versions or code paths, Atlantis could create, use, or remove/recreate out-of-bounds directories with the privileges of the Atlantis process user, before Terraform rejected the invalid workspace name.
The issue is fixed in Atlantis 0.45.0.
Details The issue is a path traversal vulnerability in Atlantis workspace handling. workspace values can be supplied through repository-level atlantis.yaml configuration accepted by the server or through authenticated API input. A value such as ../../../../../../../../tmp/f1-canary could escape the intended Atlantis workspace root.
In affected code paths, Atlantis used the resolved workspace path for local working-directory operations. For example, workspace values were joined into repo pull paths, and clone preparation paths could call directory removal/recreation operations such as os.RemoveAll and os.MkdirAll on the resolved directory.
PoC In a local PoC using repo-level atlantis.yaml, the following workspace value caused Atlantis to resolve and use /tmp/f1-canary outside ~/.atlantis/repos/...:
yaml version: 3 projects: - dir: . workspace: ../../../../../../../../tmp/f1-canary
Atlantis logs showed the out-of-bounds directory being created and Terraform being run with /tmp/f1-canary as the working directory. Terraform rejected the workspace name only after Atlantis had already used the out-of-bounds path.
Impact A user who can cause Atlantis to process a crafted workspace value, for example through repository-level atlantis.yaml configuration accepted by the server or an authenticated /api/plan request, may cause filesystem operations to occur outside the intended workspace boundary.
Depending on the affected version, code path, deployment configuration, and filesystem permissions, this may result in unintended directory creation, deletion, or reuse, integrity impact to writable local paths, or denial of service. Containerized deployments may limit host impact, but writable mounted volumes and persistent Atlantis data paths remain relevant.
Other sources
Atlantis is a self-hosted golang application that listens for Terraform pull request events via webhooks. From 0.19.8 until 0.45.0, Atlantis does not consistently validate user-controlled workspace values supplied through accepted repository-level atlantis.yaml configuration or authenticated /api/plan input before joining them into local workspace paths. Traversal segments can escape the intended per-pull workspace directory and cause clone preparation or other working-directory code paths to call os.RemoveAll, os.MkdirAll, or related filesystem operations on out-of-bounds directories before Terraform rejects the invalid workspace name. This can create, delete, or reuse writable paths with the privileges of the Atlantis process, causing integrity loss or denial of service. This issue is fixed in version 0.45.0.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
go/github.com/runatlantis/atlantisto a version that resolves this vulnerability.Fixed in 0.45.0 - Upgrade
Upgrade
Atlantisto a version that resolves this vulnerability.Fixed in 0.45.0
Event History
Frequently Asked Questions
Which deployments are exposed?
Atlantis versions from 0.19.8 up to, but not including, 0.45.0 are affected. Exposure requires a path through either an accepted repository-level atlantis.yaml configuration or the authenticated /api/plan input that supplies a user-controlled workspace value.
What access does an attacker need?
The attacker needs the ability to provide a malicious workspace value through an accepted repository configuration or to use the authenticated /api/plan endpoint. No user interaction is required after the malicious value is accepted.
What can successful exploitation do?
Traversal segments can make Atlantis filesystem operations act outside the intended per-pull workspace directory. Depending on the Atlantis process's permissions, this can create, delete, or reuse writable directories, resulting in integrity impact or denial of service.
What should teams do if they cannot upgrade immediately?
Restrict who can submit or approve repository-level atlantis.yaml configuration and who can access the authenticated /api/plan endpoint. Limit the filesystem permissions of the Atlantis process so it cannot modify sensitive directories outside its intended workspace locations.
How can teams determine whether they may already be affected?
Review Atlantis versions and treat deployments running 0.19.8 through 0.44.x as affected. Examine accepted atlantis.yaml files and authenticated /api/plan requests for workspace values containing traversal segments, and investigate unexpected directory creation or deletion performed by the Atlantis process.